I'm in need of sources for KS2 level information on radio waves and Antennas.

The reason is that my son wants to do his science project on receiving NOAA satellite weather images with a homemade antenna. I've all the parts; RTL-SDR, materials for the antenna build (This one which is about as simple as it gets for 137MHz), Raspberry pi and the software that is needed.

The only thing that is missing in some materials at KS2 level to try and help him understand how radio waves and antennas work. Is anyone aware of any materials that would be suitable?

When I was at the top end of that age-range (7 - 11,as I understand it) I borrowed M. G. Scroggie's Foundations of Wireless from the local library, and never looked back.

The author died in 1989; an 11th edition of his book was published in 1997, revised by SW & RS Amos (who also wrote Principles of Transistor Circuits, another useful book at the time).
Not very usefully, you can buy a used copy for £94.42